الفهرس 
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Abstract
The present studies were carried out in the experimental Desouk district, Kafr EL-Sheikh Governorate Egypt.to evaluate the population abundance of the scale insects and mealy bugs that infesting mango trees Mangifera indica L. during the two successive years 2014/15 and 2015/16. Furthermore, evaluating the total number and percentage of the main scale insects and mealybug species on mango trees during the two successive years, seasonality average numbers and percentage and monthly average numbers of the main scale insects and mealybug species according to the different directions of mango trees and seasonality average numbers and percentage. On the other hand, studying the effect of some insecticides on the main insect pests.1. ecological studies:1.1. The soft scale insect Kilifia acuminata (Signoret).The population density of the soft scale insect k. acuminata during the first year of study recorded 6 peaks and the highest peak recorded 1539 indiv.on 27th of March 2015 and represented by 1539 indiv, while recorded 4 peaks during the second year and the highest peak recorded on 17th of June 2016 and represented by 1178 indiv.The highest average number and percentage in the first year was recorded during autumn season and represented by 1023.1 indiv. /100 leaves (30.2%), while the highest average number and percentage was recorded during spring and represented by 994.8indiv./100 leaves (29%) in the second year. 1.2. The white mango scale insects, A. tubercularis (Newstead).The population density of white mango scale A. tubercularis during the first year of study recorded 4 peaks and the highest peak recorded on 21th of November 2015 and represented by 554 indiv, while during the second year recorded 5 peaks and the highest peak recorded on 29h of January 2016 and represented by 512 indiv.The highest average number and percentage in the first year was recorded during winter season and represented by 487.6 indiv. /100 leaves (33.2%), while during the second year the highest average number and percentage were recorded during autumn season and represented by 346 indiv. /100 leaves (27.4%).1.3. The Seychelles fluted scale (I. seychellarum).The population density of Seychelles fluted scale I. seychellarum during the first year of study recorded 4 peaks and the highest peak recorded on 10th of October 2015 and represented by 328 indiv., while during the second year recorded 4 peaks and the highest peak recorded on 11st of September 2015 and represented by 304 indiv.The highest average number and percentage in the first year was recorded during autumn season and represented by 241.5 indiv. /100 leave (37.2 %), while in the second year the highest average number was recorded during fall season and represented by 197.5 indiv. /100 leaves (33.4 %).1.4. The Egyptian fluted scale (I. aegyptiaca). The population density of I. aegyptiaca during the first year of study recorded 3 peaks the highest peak recorded on 10th of October 2015 and represented by 139 indiv, while during the second year recorded 4 peaks the highest peak recorded on 25th of September 2015 and represented by 107 indiv. The highest average number and percentage in the first year was recorded during autumn season and represented by 86.7 indiv. /100 leaves (44.1%), while during the second year the highest average number was recorded during summer season and represented by 61.5 indiv. /100 leaves (29.1%). 2. Chemical control of the studied insects: Kilifia acuminata (Signoret), Aulacaspis tubercularis (Newstead), Icerya seychellarum (Westwood) and Icerya aegyptiaca (Douglas). Field experiments were conducted in 2015 and 2016 to study the effect of seven chemical compounds Viz., methomyl, pyridalyl, hexaflumuron, emamectin-benzoate, chlorpyrifos, Super misrona and KZ oil on the above mentioned four insects on mango trees. The chemicals applied using six horse power motor and the obtained results could be summarized in the following lines. 2.1. Kilifia acuminata A- The organophosphorus insecticide, chlorpyrifos was the most potent against K. acuminata recording 84.0 % and 94.9% reduction in its population after three weeks of spray in 2015 and 2016, respectively. B- The carbamate compound, methomyl came in the second order with 82.3 % and 89.0% average effect (in 2015 and 2016, respectively) without significant differences comparing to chlorpyrifos. 2.2. Aulacaspis tubercularis. A- The obtained results indicated that methomyl and chlorpyrifos were the most effective against A. tubercularis recording from 83.4 % to 97.3 % reduction in the two years of the study. B- The activity of the tested compounds generally increased in 2016 compared with 2015. C- The two mineral oils and the chitin synthesis inhibitor, hexaflumuron exhibited insignificant differences among them in their effect on the insect recording from 62.1 to 67.7 % in 2015. But, hexaflumuron was significantly less effective than the mineral oils in 2016. 2.3. Icerya seychellarum. A-The two conventional insecticides, methomyl and chlorpyrifos, statistically proved to be the highest effective on I. seychellarum recording 87.5 and 94.9 % reduction for methomyl and 88.7 and 97.2 % reduction for chlorpyrifos 2015 and 2016, respectively. B- The mineral oils, Super Misrona and KZ, caused from 59.6 to 65.2 % average reduction in the insect infestation in 2015 and from 62.3 to 65.0 % average reduction in 2016. c-The statistical analysis revealed insignificant differences among pyridalyl, hexaflumuron and emamectin benzoate in their potency against Icerya seychellarum in 2016 where they gave from 44.7 to 54.4 % reduction. 2.4. Icerya aegyptiaca. A- In season 2015, the tested chemicals could be arranged descendingly based on the average reduction percentages as follows: methomyl (87.1 %), chlorpyrifos (82.8 %), Super Misrona (58.4%), KZ oil (57.3%), emamectin-benzoate (46.9 %), hexaflumuron (44.0%) and pyridalyl (32.4 %) reduction. B- The activity of methomyl and chlorpyrifos did not vary significantly in season 2016 causing 94.4 and 93.1 % reduction, respectively.